When did Nick Holonyak invent the LED? What purpose does the LED serve?

Nick Holonyak Jr. was an American engineer and educator.

He was best known for his 1962 invention of a light-emitting diode (LED) that emitted visible red light instead of infrared light while working at General Electric’s research laboratory in Syracuse, New York.

LEDs are semiconductor light sources that combine a P-type semiconductor (larger hole concentration) with an N-type semiconductor (larger electron concentration).

Applying a sufficient forward voltage will cause the electrons and holes to recombine at the P-N junction, releasing energy in the form of light.

Compared with conventional light sources that first convert electrical energy into heat, and then into light, LEDs (Light Emitting Diodes) convert electrical energy directly into light, delivering efficient light generation with little-wasted electricity.

Holonyak predicted that his LEDs would replace the incandescent light bulb of Thomas Edison in the February 1963 issue of Reader’s Digest, and as LEDs improve in quality and efficiency they are gradually replacing incandescents as the bulb of choice.